This invention relates to the manufacture of fiber reinforced hose and more particularly to an extruded aramid fiber reinforced hose having criss-crossing helically orientated fibers or hose with aramid fibers reinforcement.
To improve the quality of hose, it has become desirable to incorporate filamentary reinforcing materials to the hose body. One of the principle ways in which this is achieved is to wind a surface layer or layers of nonwoven filamentary material impregnated with a polymeric material around a rod or mandrel and bonding the surface layers together. As illustrated in U.S. Pat. No. 3,957,085, the strips of nonwoven material are formed from a layer of randomly disposed nylon filaments which have been subjected to the heat and pressure to fuse the filaments together and form a unitary sheet. A surface film of polymeric material such as latex rubber is applied to the matrix material. The layers of impregnated materials are then wound helically. Different layers may then be wound helically to form the hose pipe. Other prior art teachings suggest using an extruder but to introduce the material at locations other than the hopper to prevent chopping of the fibers by the rotation of the extruder screw. (See U.S. Pat. No. 3,429,003). The present invention contemplates the use of an extruder wherein the finely chopped discrete aramid filaments are mixed with the elastomer at the hopper and the mixture is worked along the full length of the barrel and extruded through the strainer plate and die head to form an aramid filament reinforced hose, wherein the filaments are inclined in opposite directions helically about the hose body to provide a hose which has unusual properties. The apparatus of this invention eliminates the numerous steps and auxiliary machinery heretofore necessary to provide the helically winding of the fiber reinforced materials.